Correct option is D
Explanation-
A. CNBr → III. -Met-Ala-
CNBr (cyanogen bromide) is a chemical reagent that cleaves peptides specifically at the C-terminal side of methionine (Met) residues. In the sequence -Met-Ala-, CNBr will cleave after Met, resulting in peptide fragments.
B. Trypsin → IV. -Arg-Gly-
Trypsin is a serine protease that cleaves at the C-terminal side of basic amino acids, particularly arginine (Arg) and lysine (Lys). In the sequence -Arg-Gly-, trypsin will cleave after Arg, producing two fragments.
C. Caspase → I. -Asp-Ala-
Caspases are proteases that function in apoptosis (programmed cell death). They recognize specific tetrapeptide motifs and cleave after aspartic acid (Asp). The sequence -Asp-Ala- represents such a cleavage site.
D. Chymotrypsin → II. -Phe-Ala-
Chymotrypsin is a digestive protease that cleaves at the C-terminal side of aromatic amino acids like phenylalanine (Phe), tyrosine (Tyr), and tryptophan (Trp). The sequence -Phe-Ala- fits its specificity, so chymotrypsin cleaves after Phe.
Final answer- Option d: A - III, B - IV, C - I, D - II
